From atanaka@mit.edu Fri Oct 07 04:58:21 1994 Path: ashpoly!cascade!brgate!saturno!mit!atanaka From: atanaka@mit.edu (Astrid Tanaka) Newsgroups: comp.dsp Subject: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct07.045821.1489@mit.edu> Date: Fri, 07 Oct 1994 04:58:21 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 10 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Astrid Tanaka Tape trading list upon request. SASE required for international mail. From fito@unam.mx Sun Oct 09 04:28:21 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!unam!fito From: fito@unam.mx (Fiona Ito) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct09.042821.8577@unam.mx> Date: Sun, 09 Oct 1994 04:28:21 GMT References: <1994Oct07.045821.1489@mit.edu> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Oct07.045821.1489@mit.edu>, atanaka@mit.edu (Astrid Tanaka) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Fiona Ito "The carrier frequency does not drift by accident." Acorn RiscPC 600 / NEXTSTEP 3.3 From aduarte@clari.net Sun Oct 09 11:44:21 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!aduarte From: aduarte@clari.net (Andrei Duarte) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct09.114421.7204@clari.net> Date: Sun, 09 Oct 1994 11:44:21 GMT References: <1994Oct07.045821.1489@mit.edu> <1994Oct09.042821.8577@unam.mx> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Oct09.042821.8577@unam.mx>, fito@unam.mx (Fiona Ito) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Andrei Duarte "They will send a copy in my place." Sun 3/60 (SunOS 4.1.1) / AmigaOS 3.1